How long did you boil? The longer the boil usually means the higher the OG. But if you measeured it hot, it will read low. Usually take a reading when the temp gets down to around 70-ish. The hydrometer is calibrated to be accurate at 60 degrees. If you take a reading at 70 degrees...add .001, and at 118 degrees, add .01. So temp makes a big diff when taking OG. Was this an all grain, partial or extraxt? AG or partial, you may have had a mis calculated recipe.

72 degrees would not make up the differance. You can go here to look up what to add for the 72 temp. Like everyone else said, post your recipe later and we can probably go from there. It is also possible that you misread your hydrometer. 1.015 is pretty much where you want to end up at, not start.

How long did you boil? The longer the boil usually means the higher the OG. But if you measeured it hot, it will read low. Usually take a reading when the temp gets down to around 70-ish. The hydrometer is calibrated to be accurate at 60 degrees. If you take a reading at 70 degrees...add .001, and at 118 degrees, add .01. So temp makes a big diff when taking OG. Was this an all grain, partial or extraxt? AG or partial, you may have had a mis calculated recipe.

Well since it was my first it was a recipe kit with all the crushed grain, extracts and hops pre-measured.

May have misread the hydr. with 6.6 lbs of ME, there should be no way to fall that short. Can you re-test OG tonight? And I assume this was a 5 gallon batch, so if you followed the directions, you should be OK.